A device for cooling an interior compartment is known from DE 43 27 866. This device has a primary cooling circuit, which comprises a compressor, a condenser, an expansion unit, and an evaporator. The evaporator is designed as a liquid/liquid heat exchanger and transfers the cold, which is generated in the primary circuit of the evaporator, to coolant of a secondary circuit. The secondary circuit includes a cold accumulator and a heat exchanger, which is used to cool the air to be supplied to a vehicle interior. The cold accumulator is arranged in series with the heat exchanger in the secondary circuit and can be bridged via a bypass.
A significant drawback of this known device for cooling an interior compartment is that, when the accumulator is being charged, the cold-transporting agent always has to flow through the heat exchanger, even when the heat exchanger is not being used, for example, because there is no need for cooling. Consequently, as the accumulator charges, the heat exchanger will become frosted, or, at the very least, condensation water will precipitate on the heat exchanger, resulting in unpleasant odors due to the presence of bacteria. The heat exchanger is usually subjected to forced flow of air, with the result that there is a constant loss of cooling capacity. A further drawback is that the cold generated in the evaporator of the primary circuit cannot be distributed as desired to the heat exchanger and the cold accumulator.
DE 196 29 114 discloses a device for cooling an interior compartment of a motor vehicle. This device also has a cold-generating primary circuit. The cold-generating circuit has an evaporator, by means of which the cold is transferred into a secondary circuit. The secondary circuit has a valve unit, by means of which the generated cold can optionally be transferred to one or two heat exchangers in order to cool the air which is to be supplied to a vehicle interior. The coolant used in the secondary circuit is a water/Glysantin mixture. A drawback of this known air-conditioning unit is that there is no cold accumulator, so that there is no standard air-conditioning or there is insufficient cooling capacity in the peak requirement range.
The difficulties suggested in the preceding are not intended to be exhaustive but rather are among many which tend to reduce the effectiveness of known cooling devices. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that such devices appearing in the past will admit to worthwhile improvement.